1. Field of the Invention
The present invention relates to a module cam assembly and a method for aligning and fastening a tool to the module cam assembly. The module cam assembly is detachably sandwiched between the upper and lower die holders of a press machine.
2. Related Art
Referring to FIG. 6, when it is desired to bend and punch work pieces using a variety of metal molds (dies) respectively having upper halves and lower halves, it is known to install a cam unit between the upper and lower die holders of a press machine. The cam unit comprises a vertically movable cam driver 22 fixed to an upper die holder 21, a horizontally movable cam slider 23 slidably connected to the cam driver 22, a positive return 24 having a resilient member responsive to the rise of the cam driver 22 for driving the cam slider 23 to the original position, and a lower die holder 25 slidably supporting the cam slider 23. The cam driver 22 has a downward cam slope, and the cam slider 23 has an upward cam slope. The cam driver 22 and the cam slider 23 are combined together with their slopes put in contact each other, so that raising and lowering of the cam driver 22 may move the cam slider 23 back and forth. The cam slider 23 is biased toward its original position in which the cam driver 22 is raised to its upper dead point, and the cam slider 23 is responsive to the rise of the cam driver 22 for moving back to the original position.
The cam slider 23 has, for example, a punch 26 fastened to its vertical side for piercing work pieces, whereas the lower holder 25 has a die 27 fastened to its vertical side corresponding to the punch 26. Such tool parts are aligned with each other to assure side piercing or side cutting of work pieces.
The above dies (cam unit) are massive and heavy and accordingly the cam driver, the cam slider and the cam base, a part of the lower die, are combined as a cam unit in order to improve its adaptability to a variety of machining of work pieces. For example, a known compact cam unit 28 that is narrow in width as shown in FIGS. 7A and 7B, comprises a cam driver 28a, a cam slider 28b, a cam base 28c, and a positive return 28d. The cam unit 28 is of a “horizontal” (die-mounted) type. As shown in FIGS. 8A and 8B, another cam unit 29 comprises a cam driver 29a, a cam slider 29b, and a cam base 29c, which is upside down compared to the above cam unit 28. The cam slider 29b is equipped with a positive return 29d. The so assembled cam unit 29 is of a “flying” (aerial) type.
Such a cam unit, however, is useless in reducing the difficulty in aligning and fastening a tool such as the punch 26 and die 27 in an exact position. The cam unit is fixedly set on the lower die holder 25, and the upper die holder 21 is raised or lowered slowly and by degrees to control the horizontal movement of the cam slider 23 until the die 27 and the punch 26 are put exactly in alignment. When aligned, the punch 26 and die 27 are tentatively fixed to the stationary and movable parts of the press machine. Then, the upper die holder 21 is raised up to the upper dead point, and the punch 26 and die 27 are fixed in position. The upper holder 21 is lowered to the lower dead point to check if the punch 26 and die 27 are aligned with each other. Usually this centering sequence is repeated until these tool parts are put exactly in alignment. JP2002-143944 (A) proposes use of a key in aligning tool parts.
As mentioned above, the aligning-and-setting work is very tedious, requiring the raising and lowering of the upper die holder for putting tool parts exactly in alignment.
One object of the present invention is to provide a module cam assembly facilitating the aligning and setting of tool parts.
Another object of the present invention is to provide a method of aligning and attaching tool parts to the stationary and movable parts of a press machine.